Slow Rendering - low CPU usage

I'm looking to switch from my ancient version of Premiere Pro (5) to something more modern, so I've been trying out Resolve 16. It appears to do what I want in the way that I want - I'm mostly a DAW user, so the user interface of Resolve is much more modern like the DAWs I use, rather than Premiere's frustrating user experience.

I'm on what I'd consider a reasonably powerful PC:
Intel i9-9900KF CPU
Corsair Vengeance LPX 32GB (2x16GB) DDR4 DRAM 2666MHz C16
Asus PRIME Z390-A Motherboard
Corsair 1TB M2 SSD Boot Drive

The only slight let-down is the GPU (which isn't critical for my music work, and has been OK in Premiere) - a GTX670.

Render times seem (to me) to be tragic - a project with a 30 second minute HD video clip (25fps) with a single stereo audio track takes nearly 2 minutes to render. When doing this I'm getting about 9% total CPU usage, and about 6% of that is Resolve (see attached).

resolve cpu render usage.PNG (101.53 KiB) Viewed 3446 times

From what I've read, the free version of resolve doesn't do GPU rendering, so I'd expect the CPU to be doing more than this, and hopefully to be much better in performance than this.

Compare the same project rendered (with GPU rendering turned off) in Premiere - 30 second render time, and usage looks like this:

prem cpu render usage.png (107.18 KiB) Viewed 3446 times

Any suggestions? I don't want to shell out on a replacement GPU if it won't make any difference, and I'm really at a loss as to why the CPU usage is so low.

You understand wrong. The free version does everything in GPU except decompressing and compressing video at input and output stages. The CPU is not used for rendering (except in Fusion tab - do you use Fusion tab?)

You really need to check the GPU graph (at the bottom), select "compute" and see how much it's being used, I suspect a lot but the GPU is slow....

Mario - thanks! I get it now... I guess I'll have to shell out on a more powerful GPU and see the improvement! Hope so, as I really like resolve to work with, even though it's early days, it's much easier to translate from DAW to it, rather than having to unload half my brain!

Did you ever try with a more modern GPU? I'm having similar problems with low CPU utilization and slow render times, but I'm using an RTX 2080, so I'm not convinced the GPU is necessarily to blame.

I'm still waiting for 3060Ti to be available at non-scalper prices (I'm guessing a couple of months) and then I'll see what my situation is - and then post the results here.

I was getting speedy render times with 16.1.1. Then I decided, hey, it's been awhile, let's update to the latest, which is 16.2.8. Render times slowed to an absolute crawl! I reverted back to 16.1.1, and now my render times are speedy again.

at non-scalper prices

I saw the 3080 I want selling for more than 2x on eBay, and Out Of Stock everywhere else.

WTF!!!

FWIW - I had VERY similar symptoms and based on a question asked of another user with also similar symptoms, and the fact that I'd been meaning to manually update my video drivers, I updated my more-than-a-year old drivers... and got a 10x improvement in performance. Something about the old graphics driver appeared to bottleneck the encoding time substantially... Now spike over 90% CPU during render and a project that took me 35m before was <3.5 minutes after. It was night and day for me, so it may be worth a shot!

Previously I said that I was getting good rendering performance with 16.1.1, but terrible performance with 16.2.8. Well, it turns out my graphics drivers were pretty old (couple years). I updated my NVIDIA drivers, and now 16.2.8 renders just as fast as 16.1.1.

Thanks for the tip!

Glad it helped someone else, too! Cheers!